C9 Engine Miss

[Mark Lorentz]

Hi Guys, My 2007 Contessa with a 2006 cat C9 400 92k has a problem.  After an hour or so of driving at highway speed‘s it develops a miss. If I turn the engine off for 10 seconds or so and restart the engine the miss is gone.
The miss will re-develop after an hour or two of driving, the miss never occurs when the engine is cold.
I took apart the fuel pressure regulator and found a piece of a very small O-ring stuck in the small bleed hole in the center of the piston I replaced the fuel pressure regulator with a new one from Cat.
I did connect a clear piece of test line to the return fuel line and saw a very good flow with no air in the fuel at all.
No codes are set no check engine light came on it does puff some black smoke when revved in neutral.
The last time it did it I hooked up Cat ET and did a cylinder cut out test and found cylinder one was dead, I turned the engine off restarted it and the cut out test showed no problem , also did an injection actuation test and that looked fine.
My question is can a bad injector be fixed temporarily by simply turning the engine off and on ?
Any one else seen this proublem

Thanks,
Mark

[Jim Nichols]

Sounds like an electrical short. Pull the injector connections and see if they’re wet with oil.  They should be dry. Spray with brake cleaner, then place universal o-rings on each and then reconnect. Dave Atherton taught me.

[Steve Huber Co-Admin]

Mark,
Jim's suggestion is a good one. The procedure for adding the O rings is documented in the summary of Dave Atherton's Seminar. It's located in the Technical Support board, about the 3rd post from the top. If I remember correctly, the O rings are 10mm.
Steve

[Mark Lorentz]

Thanks guys
I was going to pull the cover and do an overhead anyway so it will be very easy to check that.
I would be surprised though as the miss is a hard miss as in totally dead cylinder and after a restart it is completely gone for an hour or so.
So their is no doubt the restart changes something

-mark